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781.
In the present study a novel modeling approach is presented to solve the combined internal sloshing and sea-keeping problem. The model deals with interesting effects arising due to the coupled interaction between the sloshing in partially filled containers of several geometries and the ship motion. The study is very important for the liquid cargo carrier operating in rough sea or under different environmental conditions. The resulting slosh characteristics that include transient pressure variation, free surface profiles and hydrodynamic pressure over the container walls have been reported in this study. In addition, the effects of coupled ship response and sloshing on ship motion parameters have also been investigated. The equations of motion of fluid, considered inviscid, irrotational, and partially compressible, are expressed in terms of the pressure variable alone. A finite difference-based iterative time-stepping technique is employed to advance the coupled solution in the time domain. Several parameters of interest, including the container parameters, level of liquid, thrusters modeling and some important environmental factors are investigated. 相似文献
782.
C. Ma J. Kang W. Choi M. Song J. Ji H. Kim 《International Journal of Automotive Technology》2012,13(3):505-516
A comparative study was performed on two types of plug-in hybrid electric vehicles (PHEVs): the GM Volt and the Toyota Prius
Plug-in Hybrid. First, the powertrain models of the two vehicles were derived. Based on the dynamic models, a detailed component
control algorithm was developed for each PHEV. Specifically, a control algorithm was proposed for motor generator 1 (MG1)
and MG2 to achieve optimal engine operation. Additionally, an energy management strategy for selecting the operation mode
was developed from the viewpoint of fuel economy, battery state of charge and vehicle velocity. Using the dynamic model of
the control algorithm for each PHEV, simulations were performed, and the simulation results were verified by comparing them
with those obtained using the Powertrain System Analysis Toolkit simulator for the plug-in Prius. Based on the simulation
results, a comparative study was performed, and it was found that the role and capacity of MG1 and MG2 and the mode selection
algorithm must be determined depending on the configuration of the PHEV. 相似文献
783.
C. -J. Kim Y. J. Kang B. -H. Lee H. -J. Ahn 《International Journal of Automotive Technology》2012,13(3):451-458
Critical responses are frequently detected at the coupled torsional beam axle (CTBA) of a lightweight vehicle. However, the
freedom to modify the design of the axle shaft is limited because the suspension system must satisfy other vehicle requirements
such as steering performance. Conventional sensitivity analysis cannot provide practical information about the resonant behavior
because the analysis only identifies the contribution of the axle shaft to the behavior. This paper presents a novel sensitivity
analysis based on transmissibility ratios (TRs). The vehicle components other than the axle shaft that can be modified to
control the critical spectra are identified using acceleration responses. A multi-body vehicle model is constructed to simulate
the proposed design modifications, and the simulation results show that the vibration of the axle shaft is considerably reduced
by the modifications. Because the TRs on the CTBA are effectively minimized through the modified design strategy, the resonant
response from the axle shaft can be controlled efficiently. 相似文献
784.
The front end module (FEM) needs enough space from hood to absorb the energy from any pedestrian collision. The FEM with downsized cooling module for pedestrian protection is important to reduce the severity of pedestrian injury. When a vehicle collision happens, the FEM with downsized cooling module is required to reduce the risk of injury to the upper legs of adults and the heads of children. In this study, the performance of cooling module to cool the engine was investigated under 25% height reduction. The heat dissipation and pressure drop characteristics have been experimentally studied with the variation of coolant flow rate, air inlet velocity and A/C operation (on/off) for the downsized cooling module. The results indicated that the cooling performance was about 94% level compared to that of the conventional cooling module. Therefore, we concluded that the cooling module had a good performance, and expected that the cooling module could meet the same cooling performance as conventional cooling module through optimization of components efficiency. This paper also deals with the development of FEM with downsized cooling module for the cooling performance level in vehicles. In the test of front end module??s heat dissipation performance, the prototype presented about 15% decrease under the conditions of all the vehicle speeds than that of conventional one. 相似文献
785.
C. -H. Park H. -J. Shim D. -H. Choi J. -K. Kim S. -M. Lee 《International Journal of Automotive Technology》2012,13(1):61-75
Rubber isolators are mounted between a cooling module and a carrier to isolate the car body from vibration due to the rotation
of the cooling fan. The isolators should be durable against fatigue loads originating from fan rotation and road disturbance.
Thus, the design of rubber isolators is required to maximize both vibration isolation and fatigue life. In this study, the
shapes of the rubber isolators are optimally designed using a process integration and design optimization (PIDO) tool that
integrates the various computer-aided engineering (CAE) tools necessary for vibration and fatigue analyses, automates the
analysis procedure and optimizes the design solution. In this study, we use CAE models correlated to the experimental results.
A regression-based sequential approximate optimizer incorporating Process Integration, Automation and Optimization (PIAnO),
a commercial PIDO tool, is employed to handle numerically noisy responses with respect to the variation in design variables.
Using the analysis and design procedure established in this study, we successfully obtained the optimal shapes of the rubber
isolators in two different cooling modules; these shapes clearly have better vibration isolation capability and fatigue lives
than those of the baseline designs used in industry. 相似文献
786.
The controller area network (CAN) protocol is widely used for in-vehicle network (IVN) systems, and many automotive companies
also use the CAN in chassis network systems. However, the increasing number of electronic control units (ECUs) dictated by
the need for more intelligent and fuel-efficient functions requires an IVN system with a greater transmission capacity and
less network delay. Automotive companies have tried several approaches such as segmenting CAN systems and developing time-triggered
protocols. This paper presents a practical method for increasing the transmission capacity and reducing the network delay
in CAN systems using dual communication channels with a traffic-balancing algorithm based on Kalman prediction to forecast
the traffic on each channel and allocate frames to the one that is most appropriate. An experimental testbed using commercial
microcontrollers with two or more CAN protocol controllers was used to demonstrate the feasibility of the Kalman traffic-balancing
algorithm. Experimental results show that the traffic-balancing CAN system with Kalman prediction reduced the transmission
delay of all priority messages compared to that of a simple method, such as a channel-switching CAN, without sacrificing the
performance for high-priority messages. 相似文献
787.
Design of a soft switching bidirectional DC-DC power converter for ultracapacitor-battery interfaces
Z. W. Wu Z. L. Zhang C. L. Yin Z. Zhao 《International Journal of Automotive Technology》2012,13(2):325-336
One solution to the low specific power of hybrid electric vehicular batteries is a hybrid energy storage system (HESS) that
takes advantage of the high specific power performance of ultra-capacitors. The design of a type of zero current transition
(ZCT) soft switching bidirectional direct current-direct current (DC-DC) power converter that can be used as an ultra-capacitor-battery
interface in an active parallel schema of a HESS is described. The circuit operation of the ZCT DC-DC power converter is depicted
in detail. The HESS controller is designed as a two-layered hierarchical control structure: the first layer is responsible
for working mode control of the HESS, and the second layer is responsible for DC-DC power converter control in which a fuzzy
logic PID algorithmis employed. Simulation results indicate that this design is a potential solution to the problem of the
low specific power of batteries, especially for regenerative braking and electric motor assist. The proposed active parallel
schema with ZCT exhibits a significant advantage in power and energy decoupling. HESS with ZCT achieves better efficiency
compared to the battery only operation. The experimental results validates the idea that the ultra-capacitor cooperates with
the battery in acceleration mode. 相似文献
788.
Dynamic analysis of spiral bevel geared rotor systems applying finite elements and enhanced lumped parameters 总被引:2,自引:0,他引:2
X. Hua T. C. Lim T. Peng W. E. Wali 《International Journal of Automotive Technology》2012,13(1):97-107
The dynamics of spiral bevel gears like most high-speed precision gears employed in motor vehicles and off highway equipments
are substantially affected by the structural characteristics of the shafts and bearings. The lumped parameter model is one
of the common tools applied to perform gear dynamic analysis. Even though the lumped parameter approach is computationally
fast and conveniently efficient, it typically uses limited number of coordinates and may not fully account for the shaft-bearing
structural characteristics accurately. In this analysis, the finite element formulation, that can generally represent more
complete characteristics of the shaft-bearing assembly, is employed to enhance the current lumped parameter synthesis theory
using the concept of effective mass and inertia elements. Computational output shows that the enhanced lumped parameter synthesis
model is capable of predicting sufficiently accurate dynamic response when compared to the direct dynamic finite element calculations,
and much more precise response than previous lumped parameter results, especially when the gear dynamics are associated with
the pinion or gear bending modes. Even though this analysis focuses primarily on the spiral bevel geared rotor systems, the
proposed methodology and analysis results can be easily extended to other types of gears. 相似文献
789.
D. Wang Z. C. Liu J. Tian J. W. Liu J. R. Zhang 《International Journal of Automotive Technology》2012,13(7):1023-1032
Particle number measurement is a new approach to determine emission, which may be more accurate at very low emission levels than when using gravimetric measurements. An experimental study was performed to investigate the effect of fuel properties on the performance, combustion process, regulated gaseous emissions and particle number emissions of a diesel engine with an uncatalyzed diesel particulate filter (DPF). The effect of the filter on the particle size distribution was reported. The DPF number-based filtration efficiency in terms of number efficiency and fractional efficiency for petroleum diesel fuel and two alternative fuels, BTL and GTL, were analyzed. For nearly all test modes, the filter had a higher number efficiency for diesel than for BTL and GTL. The DPF fractional efficiency showed it was highly dependent on fuel type and varied widely at each size range. For diesel, the filter fractional efficiency was sufficiently high and behaved as predicted by filtration theory. For BTL and GTL, the fractional performance of the filter decreased when unexpectedly low efficiencies within the nuclei mode were exhibited. This research will be helpful in understanding DPF number-based filtration performance for alternative fuels and will provide information for the development of particulate emission control technology. 相似文献
790.